title: Comparison of arch forms between Egyptian and North American white populations.
abstract: BACKGROUND
  The aim of this study was to evaluate the morphologic differences in the mandibular arches of Egyptian and North American white subjects.
  
  
  METHODS
  The sample included 94 Egyptian subjects (35 Class I, 32 Class II, and 27 Class III) and 92 white subjects (37 Class I, 29 Class II, and 26 Class III). The subjects were grouped according to arch form types (tapered, ovoid, and square) to compare their frequency distribution between ethnic groups in each Angle classification. The most facial portions of 13 proximal contact areas were digitized on scanned images of mandibular casts to estimate the corresponding clinical bracket point for each tooth. Four linear and 2 proportional measurements were taken.
  
  
  RESULTS
  In comparing arch dimensions, intermolar width was narrower in Egyptians than in the whites (P = 0.001). There was an even frequency distribution of the 3 arch forms in the Egyptian group. On the other hand, the most frequent arch form was ovoid followed by tapered and square in the white group; the square arch form was significantly less frequent than the tapered and ovoid arch forms (P = 0.029).
  
  
  CONCLUSIONS
  The arch forms of Egyptians are narrower than those of whites. The distribution of the arch form types in Egyptians showed similar frequency, but the square arch form was less frequent in whites. It is recommended to select narrower archwires from the available variations to suit many Egyptian patients.
authors.affiliation: Postgraduate student, Department of Orthodontics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Bayome
authors.forename: Glenn T
authors.initials: GT
authors.lastname: Sameshima
authors.forename: Yoonji
authors.initials: Y
authors.lastname: Kim
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Nojima
authors.forename: Seung-Hak
authors.initials: SH
authors.lastname: Baek
authors.forename: Yoon-Ah
authors.initials: YA
authors.lastname: Kook
mesh_terms: D000293:Adolescent; D000328:Adult; D001641:Bicuspid / Q000473:pathology; D002508:Cephalometry / Q000379:methods*; D003481:Cuspid / Q000473:pathology; D003724:Dental Arch / Q000473:pathology*; D004534:Egypt; D005006:Ethnicity; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008311:Malocclusion, Angle Class I / Q000473:pathology; D008312:Malocclusion, Angle Class II / Q000473:pathology; D008313:Malocclusion, Angle Class III / Q000473:pathology; D008334:Mandible / Q000473:pathology*; D008963:Molar / Q000473:pathology; D009656:North America; D012737:Sex Factors; D044465:White People; D055815:Young Adult